The separation and analysis of chemical substances provides valuable quantitative and qualitative data for use by researchers and health care providers. Many assaying techniques have been devised which utilize sensitive chemical and instrument tests to detect both normal and abnormal components of biological fluids. In particular, the analysis of blood samples yields information which is critical to the proper diagnosis and treatment of many illnesses. To perform a blood test, a sample is obtained and then prepared for analysis by one of the many analytical procedures currently available. The preparation of the sample typically requires that the various sample components be separated in order to obtain a more nearly homogeneous specimen for testing, such as isolating blood serum which is then dispensed for analysis. The amount of serum protein, protein-bound iodine, sodium, triglycerides, salicylate, uric acid and the like can all be determined through the separation and analysis of blood components. Hence, fast and accurate methods for preparing and dispensing samples for analysis are highly desirable.
The task of conveniently and efficiently dispensing a liquid, such as a biological fluid, from a container such as a test tube is encountered routinely by lab workers in a variety of circumstances. The mouth of a test tube must be large enough for material to be readily added to the tube chamber; however, this feature makes it difficult to dispense fluid from the test tube. Conventional dispensing techniques are only marginally effective in many applications. For example, decanting a liquid from a precipitate using a stirring rod requires considerable manipulative skill and fails to provide adequate control over the volume of liquid to be dispensed. Similarly, while providing a lip or spout on a container may help direct the flow of fluid somewhat, volume control is still not attained and splashing often occurs. The transfer of liquids is more accurately controlled with a dropper pipet; however, this requires that a pipet be provided and that the pipetting operation be preformed each time a liquid sample is dispensed.
Particularly in the environment of processing and dispensing biological fluids, a simple and convenient method and apparatus are needed so that a fluid can be easily dispensed from a container such as a test tube. The present invention provides such a method and apparatus whereby virtually any liquid can be easily dispensed without the use of complicated pouring techniques and devices.